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<?php
/*
* Copyright 2007 ZXing authors
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
namespace Zxing\Common;
/**
* <p>This class implements a perspective transform in two dimensions. Given four source and four
* destination points, it will compute the transformation implied between them. The code is based
* directly upon section 3.4.2 of George Wolberg's "Digital Image Warping"; see pages 54-56.</p>
*
* @author Sean Owen
*/
final class PerspectiveTransform
{
private $a11;
private $a12;
private $a13;
private $a21;
private $a22;
private $a23;
private $a31;
private $a32;
private $a33;
private function __construct(
$a11, $a21, $a31,
$a12, $a22, $a32,
$a13, $a23, $a33
) {
$this->a11 = $a11;
$this->a12 = $a12;
$this->a13 = $a13;
$this->a21 = $a21;
$this->a22 = $a22;
$this->a23 = $a23;
$this->a31 = $a31;
$this->a32 = $a32;
$this->a33 = $a33;
}
public static function quadrilateralToQuadrilateral(
$x0, $y0,
$x1, $y1,
$x2, $y2,
$x3, $y3,
$x0p, $y0p,
$x1p, $y1p,
$x2p, $y2p,
$x3p, $y3p
) {
$qToS = self::quadrilateralToSquare($x0, $y0, $x1, $y1, $x2, $y2, $x3, $y3);
$sToQ = self::squareToQuadrilateral($x0p, $y0p, $x1p, $y1p, $x2p, $y2p, $x3p, $y3p);
return $sToQ->times($qToS);
}
public static function quadrilateralToSquare(
$x0, $y0,
$x1, $y1,
$x2, $y2,
$x3, $y3
) {
// Here, the adjoint serves as the inverse:
return self::squareToQuadrilateral($x0, $y0, $x1, $y1, $x2, $y2, $x3, $y3)->buildAdjoint();
}
public function buildAdjoint()
{
// Adjoint is the transpose of the cofactor matrix:
return new PerspectiveTransform($this->a22 * $this->a33 - $this->a23 * $this->a32,
$this->a23 * $this->a31 - $this->a21 * $this->a33,
$this->a21 * $this->a32 - $this->a22 * $this->a31,
$this->a13 * $this->a32 - $this->a12 * $this->a33,
$this->a11 * $this->a33 - $this->a13 * $this->a31,
$this->a12 * $this->a31 - $this->a11 * $this->a32,
$this->a12 * $this->a23 - $this->a13 * $this->a22,
$this->a13 * $this->a21 - $this->a11 * $this->a23,
$this->a11 * $this->a22 - $this->a12 * $this->a21);
}
public static function squareToQuadrilateral(
$x0, $y0,
$x1, $y1,
$x2, $y2,
$x3, $y3
) {
$dx3 = $x0 - $x1 + $x2 - $x3;
$dy3 = $y0 - $y1 + $y2 - $y3;
if ($dx3 == 0.0 && $dy3 == 0.0) {
// Affine
return new PerspectiveTransform($x1 - $x0, $x2 - $x1, $x0,
$y1 - $y0, $y2 - $y1, $y0,
0.0, 0.0, 1.0);
} else {
$dx1 = $x1 - $x2;
$dx2 = $x3 - $x2;
$dy1 = $y1 - $y2;
$dy2 = $y3 - $y2;
$denominator = $dx1 * $dy2 - $dx2 * $dy1;
$a13 = ($dx3 * $dy2 - $dx2 * $dy3) / $denominator;
$a23 = ($dx1 * $dy3 - $dx3 * $dy1) / $denominator;
return new PerspectiveTransform($x1 - $x0 + $a13 * $x1, $x3 - $x0 + $a23 * $x3, $x0,
$y1 - $y0 + $a13 * $y1, $y3 - $y0 + $a23 * $y3, $y0,
$a13, $a23, 1.0);
}
}
public function times($other)
{
return new PerspectiveTransform($this->a11 * $other->a11 + $this->a21 * $other->a12 + $this->a31 * $other->a13,
$this->a11 * $other->a21 + $this->a21 * $other->a22 + $this->a31 * $other->a23,
$this->a11 * $other->a31 + $this->a21 * $other->a32 + $this->a31 * $other->a33,
$this->a12 * $other->a11 + $this->a22 * $other->a12 + $this->a32 * $other->a13,
$this->a12 * $other->a21 + $this->a22 * $other->a22 + $this->a32 * $other->a23,
$this->a12 * $other->a31 + $this->a22 * $other->a32 + $this->a32 * $other->a33,
$this->a13 * $other->a11 + $this->a23 * $other->a12 + $this->a33 * $other->a13,
$this->a13 * $other->a21 + $this->a23 * $other->a22 + $this->a33 * $other->a23,
$this->a13 * $other->a31 + $this->a23 * $other->a32 + $this->a33 * $other->a33);
}
public function transformPoints(&$points, &$yValues = 0)
{
if ($yValues) {
$this->transformPoints_($points, $yValues);
return;
}
$max = count($points);
$a11 = $this->a11;
$a12 = $this->a12;
$a13 = $this->a13;
$a21 = $this->a21;
$a22 = $this->a22;
$a23 = $this->a23;
$a31 = $this->a31;
$a32 = $this->a32;
$a33 = $this->a33;
for ($i = 0; $i < $max; $i += 2) {
$x = $points[$i];
$y = $points[$i + 1];
$denominator = $a13 * $x + $a23 * $y + $a33;
$points[$i] = ($a11 * $x + $a21 * $y + $a31) / $denominator;
$points[$i + 1] = ($a12 * $x + $a22 * $y + $a32) / $denominator;
}
}
public function transformPoints_(&$xValues, &$yValues)
{
$n = count($xValues);
for ($i = 0; $i < $n; $i++) {
$x = $xValues[$i];
$y = $yValues[$i];
$denominator = $this->a13 * $x + $this->a23 * $y + $this->a33;
$xValues[$i] = ($this->a11 * $x + $this->a21 * $y + $this->a31) / $denominator;
$yValues[$i] = ($this->a12 * $x + $this->a22 * $y + $this->a32) / $denominator;
}
}
}
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